I have never understood why religious people put forward this argument. Yes, let us suppose every atrocity of the 20th century -- from mass murder
to littering --- was perpetrated by atheists.

So what? Why does that say anything about the possible existence of God? There is no valid reasoning from the premise "P is nasty" to the
conclusion "P is false".

Books such as Berlinski's are written in total bad faith -- their purpose is neither to argue nor to convince, but to intimidate by slander.
That in doing so, they make religion look as bad as atheism, is a point that never seems to occur to them.